Merge tag 'u-boot-stm32-20211213' of https://source.denx.de/u-boot/custodians/u-boot-stm

- enable KSZ90x1 PHY driver on DHCOR
- DHSOM boards:
  - increase USB power-good delay
  - add update_sf script to install U-Boot into SF
  - increase PHY auto-negotiation timeout to 20 seconds
  - fix SoM and board coding strap GPIO handling

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